Many health problems can occur as a result of diabetes.

In the short term, there is ketone damage, extreme thirst, exhaustion, nausea, and slow healing of wounds.

If diabetes remains untreated and the blood-glucose level stays high for many years, damage to nerves and blood vessels can occur. This in turn leads to the more serious complications associated with diabetes such as:

• High blood pressure
• High cholesterol
• Blood-clotting
• Heart failure
• Eye diseases including diabetic retinopathy, glaucoma, cataracts
• Strokes
• Impotence
• Foot ulcers leading to amputations
• Renal disease

The most important difference between Type 1 and Type 2 diabetes is that Type 2 diabetes is preventable. Although it has a genetic basis, Type 2 diabetes is very dependent on environmental factors. The misshapen "key holes" in Type 2 diabetes which stop insulin from entering the cells are almost always caused by excess fat or inactivity; in fact 90 percent of people with Type 2 diabetes are overweight or obese. Losing weight and increasing physical activity can help treat or prevent Type 2 diabetes in most cases.

Type 1 diabetes, on the other hand, is a hereditary condition where the problem is lack of insulin.  Type 1 diabetes must be managed through insulin injections as well as carefully-monitored eating and regular exercise. Although the causes of Type 1 and 2 diabetes are different, both forms of the disease are equally serious and have equally serious consequences if left untreated.

There is also a third type of diabetes called gestational diabetes. Gestational diabetes occurs during pregnancy, but with proper management the condition usually resolves itself after the baby is born. Gestational diabetes occurs in about eight percent of pregnancies. 

Type 1 diabetes is mostly genetic and usually occurs in children or young adults. Researchers believe that in Type 1 diabetes the body’s immune system is somehow environmentally triggered to destroy the cells in the pancreas that produce insulin. But why this happens is not understood.

Overweight and inactive adults are the people most likely to develop Type 2 diabetes. Obesity, a family history of diabetes, high blood pressure, a previous diagnosis of gestational diabetes, delivery of a baby over 9 lbs, and pre-diabetes (see the section 'What is pre-diabetes?' below) are also common factors in people predisposed to the disease. In the United States people of African-American, Native American, Hispanic, Native Hawaiian and Chinese descent are at a higher risk of Type 2 diabetes than those of European descent.